Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is fully covered. The description adds a business rule ('Funding is credited only after verified payment processing'), which explains why some entries may appear pending, but says nothing about result ordering, cursoring direction, or page-completeness behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences with no filler, and the core purpose is front-loaded. The second sentence is a slight non sequitur to the tool's mechanics but carries genuine domain context.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple two-param read tool with full schema coverage and annotations, the definition is adequate, and the mention of a returned pagination cursor partially compensates for the absent output schema. However, the ordering of entries and how the returned cursor maps to the `before` parameter remain unstated.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both `limit` (default 50) and `before` (ledger identifier) are already documented in the schema. The description adds no syntax, ordering, or cursor-chaining detail, so baseline 3 is correct.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb ('Read') and resource ('balance activity') and notes it also returns a pagination cursor, so an agent can tell this is a ledger-listing tool. It does not differentiate from related siblings like get_wallet or list_payments, leaving ambiguity about which source to consult for balance vs. payment history.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no explicit when-to-use guidance and no mention of alternatives such as list_payments or get_wallet. The agent must infer the choice from tool names alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.